Fractional condenser for separating hydrocarbons in distilling petroleum.



J. W. VAN DYKE & W. M. IRISH.

FRAGTIONAL CONDENSER FOR SBPARATING HYDROCARBONS m DISTILLING PETROLEUM.

APPLIOATION FILED APR. 18, 1911 Patented M... 9, 1915.

UNITED STATES PATENT OFFICE.

JOHN W. VAN DYKE AND WILLIAM H. IRISH, 0F PHILADELPHIA, PENNSYLVANIA, ASSIGNORS TO THE ATLANTIC REFINING COMPANY, OF PHILADELPHIA, PENNSYII" VANIA, A CORPORATION OF PENNSYLVANIA.

FRACTIONAL connnnsnn son Specification of Letters Patent.

SEPARATING HYDROCARBONS IN DISTILLING PETROLEUM.

Patented Mar. 9, 1915.

Original application filed October 4, 1909, Serial No. 520.937. Divided and this application filed Apri 18,

To all whom it may concern:

Be it known that we, JOHN W. VAN DYKE and \VILLIAM M. IRISH, both of us citizens of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Fractional Condensers for Separating Hydrocarbons in Distilling Petroleum, of which the following is a specification.

This invention relates more particularly to the distillation of petroleum in the form of an undi stilied residue, the distillation being performed at the high temperatures necessary to evaporate hydrocarbons with boiling points above 600 F. or above the temperature of commencement of cracking when this is below 600 F.; but the invention extends also to the distillation at such temperatures of petroleum in the form of a distillate and to the distillation of distillate and of undistilled petroleum at lower temperatures.

Each of the improvements composing the invention is intended to be secured for all the uses to which it can be applied, with or without modification.

The object of the invent-ion is to effect a more perfect separation from each other than heretofore of hydrocarbons which are evolved as a mass of mixed vapors and are then subjected to partial condensation, in order by such separation to obtain distillate which in its different portions shall be available for the respective uses of said portion, as far as possible, without redistillation of the same.

In the prior current practice the distillation of crude petroleum for burning oil (kerosene) as the primary product has been performed in stills with their tops exposed (fully or with slight protection only) to the atmosphere for cooling; while the distillation for lubricant stock as the primary (distillate) product (or for lubricant stock and wax yielding material, when the petroleum is of a kind to yield parafiin wax) has been performed in stills (termed tar stills) which have their tops protected for keeping the vapors hot. Residual oil from which burning oil (kerosene) has been obtained has been transferred from said exposed top stills to Serial No: 621,904.

said tar stills with intermediate cooling, set tling and storage and withsubjection of the; residual oil to treatment with'sulfuric acid or to other special treatment when required. In both of said forms of distillation a Separation of hydrocarbons from each other by partial condensation has been performed, namely, for the most part at least, in the still itself (whose exposed top forms a species of air cooled condenser) in the production of burning oil (kerosene), the vapors passing over with little, if any, further c0n' densation to a water cooled condenser and, for the most part at least, after the mixed vapors have left the still in the production of lubricant stock (or lubricant and wax yielding material), the vapors passing over through a series of two air cooled condensers to a water cooled condenser. These air cooled condensers have consisted each of a single pipe of large diameter inclined upward and cooled merely by exposure to the atmosphere. The separation of hydrocarbons in saidprior current practice has been very imperfect for various reasons. One cause is the lack of control over the cooling effect produced on the vapors. While installations have differed in the area and degree of exposure of the air cooled (condensing) walls, according to the views of the manufacturer, the cooling efi'ect produced on the vapors with any given installation has been customarily controlled solely through regulation of the still fires. By slackening these, evaporation in the still can be lessened; and as less heat is thenim parted by the vapors to the condensing walls, the latter thereupon fall in temperature and so condense a larger proportion of the passing vapors (althoughthe absolute volume condensed is smaller than before). By urging the fires, evaporation is increased; and said condensing walls consequently rise in temperature and so condense a smaller proportion (but more absolutely) of the sirable (if at all) by regulation of still fires;

and, besides, it is not possible to insure a perfect regulation of the fires at all times. The cooling also itself of the vapors has not been thorough in saidprior current practice; nor has 'proper opportunity been afforded for interchange of hydrocarbons between the condensate and the vapors.

Various proposals have been made for improving the separation of petroleum hydrocarbons by partial condensations of their mixed vapors; but in spite of them the prior current practice has been as stated. By reason of the imperfect separation, different cuts of distillate have contained hydrocarbons which, if not positively obectionable therein, could be more advantageously utilized as constituents of other cuts. For example, hydrocarbons which are sufficiently colorless and are otherwise suited for water white burning oil (kerosene) .distillate are made (as a result of imperfect separation) to pass into distillate of poorer quality; because they are accompanied by hydrocarbons too highly colored or otherwise unsuited for water white oil. In like manner the yield of lubricant stock (or of lubricant stock and wax yielding material) is diminished by imperfect separation; because thisresults in the first of the desired hydrocarbons being accompanied by hydrocarbons which are undesirable in such stock (or material), When, by reason of imperfect separation of hydrocarbons, a given out of distillate is unsuitedto the use to which it can most profitably be applied, it has to be redistilled (at corresponding expense) 1n order to fit it therefor.

In accordance with the invention, the following general features are employed: First; the body of vapors evolved in the still is divided into numerous streams which are separated from one another by heat conducting walls; second, the vapors are cooled conduc tively by means of aeriform fluid flowing over saidheat conducting walls; third, sa1d cooling is regulated from time to time by alterations of cooling effect distinct from those produced by regulation of the still fires; fourth, the resulting condensate is brought intointimate contact with the vapors for interchange of hydrocarbons, and fifth, part at least of such contact is brought about while the vapors and condensate are protected against indirect cooling to the extent at least of the cooling by which the condensate is formed. The uncondensed part of the vapors passes on to one or more other condensers. Special features, hereinafter set forth, are also employed. While it is considered necessary to the best result that all of these features (gen eral and special) should be used together; because the manner of cooling (including the feature of control or regulation thereof) 1,1ao,sea

modifies the composition'of the vapors and the condensate between which hydrocarbons are interchanged; and the final result is due to the joint action of the cooling and the interchange; it is believed that advantage over the prior state of the art is obtainable with less than all of said features; and many omissions and other changes can, therefore, be made within the limits of the invention Distillation in accordance with the present invention is primarily designed to be performed under atmospheric pressure and without introduction of steam or other aeriform fluid into the still; but working under other pressures (as under partial vacuum,

for example,) and with injection of steam or other aeriform fluid into the still, or with either of these features separately, may .to some extent at least be employed, if so desired.

The invention comprises all and singular the new, useful and original parts, improvements and combinations herein claimed.

In the accompanying drawings: Figure 1 is a view, partly in perspective and partly in vertical section, of a series of condensers the first of which is constructed in accordance with the invention; Fig. 2 is a detail View of a portion of said first condenserof the series; Fig. 3 is a diagram illustrating a modifiedformof the same condenser, and Fig. 4 is a detail view illustrating a relief valve for a pipe in a condenser of such modified form.

The mixed vapors are conveyed to the first condenser of the series by a pipe in. froin the still (not shown) which would best be well jacketed; so as to protect the vapors against undue cooling before they leave the still. Said condenser is in the form of numerous pipes 2 arranged in parallel between header 3 and chamber 4. .These pipes are cooled exteriorly; and in passing through them the vapors flow between heat conducting walls (to wit, of said pipes 2) which are closely approached in comparison with the walls of a still of ordinary cheese box form or of ordinary horizontal cylindrical form. In Fig. 1 the vapor "outlet ends of these pipes are at a higher level than their vapor inlet ends; so that the condensate, which is formed in each pipe and naturally runs downward, will flow oppositely to the correspondingstream of vapors. equalize the flow of vapors among these pipes, the aggregate cross section of the petstioned wlth reference tothe passage of the predetermined volume of vapors per unit of posed to cooling in pipes of given length,-

their average cross sections are made greater than those at said narrowest points'and the In order. to

sages at their narrowest points is proporoutlet ends of said pipes are strictured (or made smaller than said average cross section). Said strictured outlets may well constitute the narrowest points. .Means are provided for automatically releasing the pressure in said pipes should it become excessive at any time. The best arrangement is shown in Fig. 3, in which the strictured outlet 5 is formed in the body of a light valve 6 which rests by its own weight over the end of the pipe. There may be such a valve in each of said pipes; but the pressure could, of course, be released without having so many valves. While dimensions and proportions can be varied, good results have been attained for a still holding a thousand barrels of oil up to the usual level with an air cooled condenser having fifty six of the pipes 2, each eleven feet in length and four inches in external diameter (giving about 665 square feet of cooling surface on the closely approached heat conducting walls of pipes 2). A circular vapor outlet opening 5 of an inch and a quarter diameter would suffice for each pipe 2, the vapor pipe 71. having an internal diameter of twelve inches and the valve 6 weighing about thirty three ounces each.

The pipes 2 are disposed for cooling by controllable currents of the aeriform cooling fluid flowing transversely to and longitudinally of said pipes. The header 3 is annular and forms part of a passage for the cooling fluid in the middle of the group of pipes 2; while the top of the chamber 4 is a circular disk and obstructs such passage at its bottom; and the pipes 2 are inclosed in a casing 7 which fits around the header 3 at the top and has inlet openings 8 at the bottom for inflow of air from the surrounding atmosphere. Each inlet is provided with a valve 9. which can be opened. wholly or in part. or can be completely closed, as may be desired. Air currents are produced in the casing 7 hr heat absorbed from the walls of pipes 2. The vapor pipe It leads from the still directly to the'chamber 4 in Fig. 1. This chamber is much deeper than a mere manifold or header (the depthrepresented being about three-fourths the length of pipes 2). It is provided with a non-conducting (or heat retaining) jacket 10. In it. resting on the grate 11, are pieces 12 of solid material, say cobble stones of four to eight inches in diameter. The condensate from pipes 2 flows down over said stones and is given by them a back and forth transverse motion; while the vapors which rise upward between them are similarly deflected; and the vapors then pass into the pipes 2 for cooling couductively in distinct streams of small diameter.

The vapor outlet of the air cooled partial condenser 2, 3.4 is connected by pipe 13 with the vapor inlet of a second partial condenser 14 composed of numerous pipes set between readers and exposed to the air for cooling. The vapor outlet from condenser 14 is connected by pipe 15with a water cooled condenser, shown in the form of a coil 16 placed in a. water tank 1?. which is supported on walls 18 and cross beams 19. Thus. as shown, the vapors from the still flow successively through two partial condensers each of them cooled by aeriform fluid, and then through awater cooled condenser. The liquid outlets 20' and 21 of the partial condensers are respectively connected through U. traps with the water cooled draw 01f pipes and 23. placed in water tank 17. The water cooled draw off 22 is valved and is connected with outlet 20 by means of a cross which also serves to connect said outlet with two other valved pipes 24 and 25 respectively, pipe 24 being a draw of? for condensate from the chamber iwhensaid condensate becomes too thick to flow at the temperature of the water in tank 17, and pipe 25 being a run back leading to the still. The pipe 24 is maintained at a. higher temperature than the draw off It may have such higher temperature merely because exposed to the air instead of being immersed in the water of tank 17; or additional means of securing higher temperatures can be provided. At 26 is a cover to exclude rain, in case the stillstands out of doors; and the partial condenser 14 may well be similarly protected. A valved pipe 27 shown in dotted lines can be used as a run back, if desired, between the condenser 14 and the still.

The vapors generated in still pass by pipe 72. to chamber 4; and on reaching the top of said chamber 4 they are divided into numerous streams, one for each of the pipes These streams flow in parallel inside the closely approached heat conducting walls of said pipes and are severally surrounded by aeriform fluid (atmospheric air)' for cooling and are further equalized among themselves by the stricturing which they are given at their outlets by passage through the restricted openings 5 (Fig. 3). Should the pressure become excessive, one or more of the valves 6 rise and automatically re lease the pressure, the released vapors passing on to condenser 14. The vapors flow in opposite directions in pipes 2 to the corresponding streams of condensate formed by the cooling in the same; and a good opportunity for exchange of hydrocarbons between them is .thus afforded, more volatile hydrocarbons in the condensate replacing less volatile in the vapors. The flow of the aeriform fiuid'transversely to and longitudinall'y of pipes 2 over and between the same tends to uniform and eflicient cooling of the vapors. Such currents are given force and direction by their lateral confinement; while the cooling can be regulated by opening and closing the valves 9. The vapors in chamber 4 are brought into intimate contact with the condensate for interchange of hydrocarbons, while they are protected against indirect cooling. Useful but not so good results are obtainable without the pieces 12. The same is true with respect to the jacket on chamber 4.

The present invention is primarily designed for use in distilling petroleum as set forth in our application of October 4, 1909, No. 520,937, which eventuated on September 16, 1913, in Patent 1,073,548; and ofwhich application the application for the present patent is a division and continua tion, the division being made solely in consequence of oflicial requirement; but the present invention is not restricted to such use: and, when so employed, it forms but part of the features whose joint use is essential to the subject-matter of application 520,937 as restricted in accordance with said oflicial requirement of division. Moreover, the processes and apparatus of application 520,937 can be realized (with advantage over the prior state of the art and within the scope of the latter application) by the use of other known or suitable appliances of condensation, as well as by the appliances of condensation recited in the claims hereof. One mode of distilling in accordance with our said application 520,937 involves a complete distillation of crude petroleum in a continuous run. In such distillation the still is supplied with the proper charge of crude oil (say a thousand barrels). It is then heated by fires underneath to vaporizing temperatures; and the heating iscontinued with gradual rise of temperature until the still conteuts become dry or nearly so, wax tailings (of a gravity equivalent to 10 B. or heavier at (30 F.) coming over as the last distillate. Vhile the oil in the still is attaining a temperature of say 600 F. the temperature in header 3 may well rise to above 400 F. (480 F. was observed in a test run) and as the oil in distillation rises above 600 F. (say, finally to 850 E, which has been observed) the temperature in the header 3 would best be between 400 F. and (300 F. (temperatures of from 470 F. to 607 F. were observed in said test run) al though near the end of the run the flow of vapors may become so small that the tem perature in said header 3 would fall below 400 F. (317 F. was observed in said test run). It will thus be perceived that the partial condensation in said condenser 2. 3, 4 is effected at temperatures above 212 F.;

r and hence an aeriform fluid (inasmuch as it can be heated to any desired degree) is better as a. cooling agent than water would be. Another advantage of aeriform fluid over water (and, in fact, over any liquid) is that the cooling is more gradual, owing in 7 part at least to lower specific heat; and hence the vapors in contact with the heat conducting walls may be more nearly equal in temperature to those in the middle of the passing streams of vapors. The best agent is atmospheric air; but the use of other aeriform fluids is not necessarily excluded. The condensate formed in the condenser 2,

3, L is returned to the still during the earlier part of the run, say until the oil in distillation reaches about (00 F. (the run back 25 being then open and the draw offs 22 and 24 closed). Afterward the run back 25 is closed; and the condensate from condenser 2, 3, 4 iscollected as distillate through the draw ofls 22 and 24., running through the former while it remains sufliciently fluid to do so. In the test run mentioned, while the draw off 22 remained open, condensate representing more than half the vapors received. during such period from vapor pipe h was collected as distillate by draw off 22. Itwould seldom (if ever) be desired to effect the condensation in said condenser 2, 3, 4 of less than 25% of the vapors passing through; but a less condensation is not necessarily excluded. The fractional condenser 2, 3, 4 would be in accordance with the present invention, whether the condensate is returned to the still for reevaporation or is collected as distillate. So also would it be in accordance with the present invention, whether the vapors passing on by pipe 13 are I or are not subjected to further partial condensation. As shown there is further partial condensation in the-air cooled condenser 14 of vapors from pipe 13 and a complete condensation (except very light products) in water cooled condenser 16 of vapors which escape condensation in the condenser 14. The condensate from this latter is collected as distillate through the draw off 23; but if run back 27 should be provided (as indicated in dotted lines), such condensate could on occasion (say in case it should be unsatisfactory as distillate) be returned by said run back to the still for revaporation. The air inlet valves 9 would be more nearly closed at the beginning of each run,

when light hydrocarbons are being distilled,

and also at the end of each run when the volume of vapors is comparatively small,

then they would be during the intermediate part of the run. In other words, the currents of cooling fluid are controlled to increase and decrease in a general way the cooling effect on the vapors according to the varying volume and temperature of the latter. Said air inlet valves 9 would also be closed more when the weather is cold or windy and less (if at all) when it is warm or still. The valves 9- can also be manipulated to counteract or to compensate for other va' riables. In general observation of the 1301 aaeaaa from condenser .14 during the time (18' hours) in which the oil in distillation was rising from 600 F. to about 700 R, an average collection of distillate of 12 barrels per hour. In the same run, 64 barrels of distillate were received from condenser 16 and'113 barrels from-condenser 1 1 and 257 barrels from condenser 2, 3, 4 during the ,time (17 hours) in which the run was completed after the oil in distillation had attained about 700 R, an average collection during this period from the two condensers l6 and 14 (together) of 10, barrels per hour and from all three condensers of 25% barrels per hour. a

In .Fig. 3 a jacketed chamber 30 with pieces 12-of solid material loosely piled together receives the vapors from the still and is provided with the same run back and draw off pipes 22, 24 and 25 as the chamber 1. From the upper part of said chamber 30 the vapors flow by pipe 31 into the annular header 32, which corresponds with the header 3 of Fig. 1, except that it now forms the inlet to pipes 2 instead of the outlet therefrom. The vapors being made to flow downward through the pipes 2 equalize themselves among the several streams therein, without requiring the latter to be limited in their aggregate cross section; because the tendency is to check the flow of. vapors through the hotter pipes; but strictured outlet openings and means for releasing pressure automatically can be used, as indicated (for example) in Fig. 5; in which a valve 33 v having a restricted opening 34 therein is upheld by the slight pressure of a spring 351 The condensate from pipes 2 falls into pan 39 and flows by pipe 40 to the perforated annular pipe 36; which distributes it over the top of the loose pile of pieces 12. The vapors uncondensed in chamber 30 and pipes 2 pass through chamber 37 and pipe 38 into condenser 14; which corresponds with the similarly numbered part in Fig. 1. In both arrangements, opportunity is afforded for interchange of hydrocarbons between vapors and condensate by bringing them into intimate contact with each other (in chamber 4 or 30) while less exposed to indirect cooling than they are during the formation of said condensate (in pipes 2);

andin both arrangements such protection against indirect cooling results from the joint use (first) of a heat retaining jacket applied to the chamber 4 or 30, andnot to the pipes 2, (second) of a chamber 4 or 30 whose section transverse to the vapor flow is larger than that of each cooling pipe 2, and (third) of devices (stones) in said chamber 4 or 30 and not in the cooling pipes 2 for giving transverse movements back and forth to fluid passing through the same. But by the use of any one or two only of these three features, and even by other suitable dispositions, the vapors and condensate could be brought into intimate contact with each other while less exposed to indirect cooling than they are during the formation of condensate. The condensate may advantage, ously be brought also into intimate contact with the oppositely flowing vapors (as it is in pipes 2 of Fig. 1) during the cooling by which condensate is formed.

The pipe n is normally closed, but is opened for a short time at the end of the run to allow the vapors to be expelled by steam from the still in accordance with an invention of ours which was originally claimed in our said application of October 4, 1909, No. 520,937 and is now claimed in Patent 1,095,438, issued May 5, 1914, on our divisional application No. 621,905 of even date of filing with the application for the present patent, the division being made solely in consequence of oflicial requirement. In compliance with a further ofiicial requirement of division, we have filed, to wit, on May 6, 1914, application No. 836,696 as a division and continuation of the application for the present patent, and consequently also of original application of October 4, 1909, No. 520,937. Our claims in said application 836,696 cover either certain improvements in distilling petroleum or certain apparatus therefor; and each of said claims recites other matters in addition to fractional condensation or a fractional condenser. They are also further distinguished from our claims herein in omitting to recite features of the fractional condenser which are recited in our claims herein, one or more of said features in each claim herein. The features so recited in claims herein and not in claims in our application 836,696 are not necessarily employed in carrying out the subject-matter of any claim in said application 836,696.

\Ve claim herein as our invention or discovery:

1. A fractional condenser for separating hydrocarbons from each other in distilling petroleum, the same being arranged to receive vapors of the hydrocarbons to be separated and to discharge the condensate formed from said vapors and the uncondensed vapors, and including 1) appliances for dividing the vapors received by said hydrocarbons from condenser into numerous streams separated from each other by heat conducting walls and flowing in directions which are largely at least vertical and for causing laterally confined currents of aeriform cooling fluid to flow over said walls and between said streams in directions which also are largely at least vertical, and (2) valves for varying the volume of said currents of aeriform cooling fluid, substantially as described.

2. A fractional condenser for separating each other in distilling petroleum, the same having (1) an inlet below for vapors of the hydrocarbons to be separated, ('2) an outlet above for uncondensed vapors, and (3) an outlet below for condensate, and also including (4) appliances for dividing said vapors into numerous ascending streams separated from each other by heat conducting walls and for causing laterally confined currents of aeriform cooling fluid to flow over said walls and between said streams, and (5) valves for varying the volume of said currents of aeriform cooling fluid, substantially as described.

3. A fractional condenser for separating hydrocarbons from each other in distilling petroleum, the same consisting of (1) a number of vertically disposed pipes arranged to receive vapors of the hydrocarbons to be separated and to discharge the condensate formed from said vapors and the uncondensed vapors, (2) a surrounding casing arranged for the introduction of air into and its escape from the same, and (3) means for regulating the volume of air supplied to said casing, substantially as described.

4. A fractional condenser for separating hydrocarbons'from each other in distilling petroleum, the same consisting of (1) a number of pipes arranged to be cooled and to receive vapors of the hydrocarbons to be separated and to discharge the condensate formed from said vapors and the unconand for automatically reliev- I header, (2) a chamber, (3) a number of vertically disposed pipes communicating at opposite ends with said annular header and said chamber respectively, and inclosing said pipes and open to the air at one end through said'header and at other end through lateral openings, substantially as described.

6. A fractional condenser for separating hydrocarbons from each other in distilling petroleum, ceive vapors of the hydrocarbons to be separated and to discharge the condensate formed from said vapors and the 111100111 densed vapors, and including (1) a cooler portion in which" the vapors are conductively cooled, and (2) a warmer portion which is provided with a heat retaining (4) a casing the same being arranged to rethe p jacket and in which condensate from said cooler portion is brought into intimate contact with vapors of higher temperature for interchange of hydrocarbons between them, substantially as described,

In testimony whereof we aflix our signatures in presence of two witnesses.

JOHN W. VAN DYKE. WILLIAM M. IRISH Witnesses:

W. D. ANDERSON, C. E. Warm. 

